diff options
Diffstat (limited to 'Lib')
| -rwxr-xr-x | Lib/tarfile.py | 2 | ||||
| -rw-r--r-- | Lib/test/recursion.tar | bin | 0 -> 516 bytes | |||
| -rw-r--r-- | Lib/test/test_tarfile.py | 7 |
3 files changed, 9 insertions, 0 deletions
diff --git a/Lib/tarfile.py b/Lib/tarfile.py index 999a99b978..8015fae7a6 100755 --- a/Lib/tarfile.py +++ b/Lib/tarfile.py @@ -1221,6 +1221,8 @@ class TarInfo(object): length, keyword = match.groups() length = int(length) + if length == 0: + raise InvalidHeaderError("invalid header") value = buf[match.end(2) + 1:match.start(1) + length - 1] # Normally, we could just use "utf-8" as the encoding and "strict" diff --git a/Lib/test/recursion.tar b/Lib/test/recursion.tar Binary files differnew file mode 100644 index 0000000000..b823725196 --- /dev/null +++ b/Lib/test/recursion.tar diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py index 1efb841bb2..2438fd3abf 100644 --- a/Lib/test/test_tarfile.py +++ b/Lib/test/test_tarfile.py @@ -394,6 +394,13 @@ class CommonReadTest(ReadTest): with self.assertRaisesRegex(tarfile.ReadError, "unexpected end of data"): tar.extractfile(t).read() + def test_length_zero_header(self): + # bpo-39017 (CVE-2019-20907): reading a zero-length header should fail + # with an exception + with self.assertRaisesRegex(tarfile.ReadError, "file could not be opened successfully"): + with tarfile.open(support.findfile('recursion.tar')) as tar: + pass + class MiscReadTestBase(CommonReadTest): def requires_name_attribute(self): pass |